[PATCH v2 2/4] can: rockchip: add RK3588 CAN support

[1579567540@qq.com]

From: Cunhao Lu <1579567540@qq.com>

Add support for the RK3588 CAN controller by introducing a dedicated
model ID and OF match entry.

The block is closely related to the existing RK3568 variants, but it
cannot reuse their match data unchanged. In particular, RK3588
encodes RX_FIFO_CNT in bits 7:5 instead of 6:4, so the RX path needs
SoC-specific handling.

The RX FIFO count bitfield difference was found by comparing Rockchip's
vendor kernel 6.1 CAN support for RK3568 and RK3588. Runtime testing on
RK3588 also confirms that bits 7:5 are needed.

Enable the existing erratum 5 empty-FIFO workaround for RK3588.
Heiko reproduced erratum 6 on RK3588, so enable that workaround as
well.

Keep RKCANFD_QUIRK_CANFD_BROKEN enabled for RK3588, so CAN-FD stays
disabled for now. Local testing did not reproduce the two known CAN-FD
trigger frames that cause Error Interrupts on RK3568 variants. Instead,
RK3588 shows a different CAN-FD failure mode: CAN-FD frames without BRS
work in this setup, but BRS with a data bitrate different from the
nominal bitrate immediately drives the controller bus-off.

Reported-by: Heiko Stuebner <heiko.stuebner@cherry.de>
Link: https://lore.kernel.org/lkml/20260630164336.3444550-4-heiko@sntech.de/

Signed-off-by: Cunhao Lu <1579567540@qq.com>
---
 .../net/can/rockchip/rockchip_canfd-core.c    | 12 +++++++++
 drivers/net/can/rockchip/rockchip_canfd-rx.c  |  5 +++-
 drivers/net/can/rockchip/rockchip_canfd.h     | 26 ++++++++++++++++++-
 3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/rockchip/rockchip_canfd-core.c b/drivers/net/can/rockchip/rockchip_canfd-core.c
index 29de0c01e4ed..178d69edf1bb 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-core.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-core.c
@@ -50,6 +50,13 @@ static const struct rkcanfd_devtype_data rkcanfd_devtype_data_rk3568v3 = {
 		RKCANFD_QUIRK_CANFD_BROKEN,
 };
 
+static const struct rkcanfd_devtype_data rkcanfd_devtype_data_rk3588 = {
+	.model = RKCANFD_MODEL_RK3588,
+	.quirks = RKCANFD_QUIRK_RK3568_ERRATUM_5 |
+		RKCANFD_QUIRK_RK3568_ERRATUM_6 |
+		RKCANFD_QUIRK_CANFD_BROKEN,
+};
+
 static const char *__rkcanfd_get_model_str(enum rkcanfd_model model)
 {
 	switch (model) {
@@ -57,6 +64,8 @@ static const char *__rkcanfd_get_model_str(enum rkcanfd_model model)
 		return "rk3568v2";
 	case RKCANFD_MODEL_RK3568V3:
 		return "rk3568v3";
+	case RKCANFD_MODEL_RK3588:
+		return "rk3588";
 	}
 
 	return "<unknown>";
@@ -846,6 +855,9 @@ static const struct of_device_id rkcanfd_of_match[] = {
 	}, {
 		.compatible = "rockchip,rk3568v3-canfd",
 		.data = &rkcanfd_devtype_data_rk3568v3,
+	}, {
+		.compatible = "rockchip,rk3588-canfd",
+		.data = &rkcanfd_devtype_data_rk3588,
 	}, {
 		/* sentinel */
 	},
diff --git a/drivers/net/can/rockchip/rockchip_canfd-rx.c b/drivers/net/can/rockchip/rockchip_canfd-rx.c
index 475c0409e215..24e87daa1df0 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-rx.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-rx.c
@@ -281,7 +281,10 @@ rkcanfd_rx_fifo_get_len(const struct rkcanfd_priv *priv)
 {
 	const u32 reg = rkcanfd_read(priv, RKCANFD_REG_RX_FIFO_CTRL);
 
-	return FIELD_GET(RKCANFD_REG_RX_FIFO_CTRL_RX_FIFO_CNT, reg);
+	if (priv->devtype_data.model == RKCANFD_MODEL_RK3588)
+		return FIELD_GET(RKCANFD_REG_RX_FIFO_CTRL_RX_FIFO_CNT_RK3588, reg);
+
+	return FIELD_GET(RKCANFD_REG_RX_FIFO_CTRL_RX_FIFO_CNT_RK3568, reg);
 }
 
 int rkcanfd_handle_rx_int(struct rkcanfd_priv *priv)
diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
index 93131c7d7f54..82a617e4ca66 100644
--- a/drivers/net/can/rockchip/rockchip_canfd.h
+++ b/drivers/net/can/rockchip/rockchip_canfd.h
@@ -214,7 +214,8 @@
 #define RKCANFD_REG_TXEVENT_FIFO_CTRL_TXE_FIFO_ENABLE BIT(0)
 
 #define RKCANFD_REG_RX_FIFO_CTRL 0x118
-#define RKCANFD_REG_RX_FIFO_CTRL_RX_FIFO_CNT GENMASK(6, 4)
+#define RKCANFD_REG_RX_FIFO_CTRL_RX_FIFO_CNT_RK3568 GENMASK(6, 4)
+#define RKCANFD_REG_RX_FIFO_CTRL_RX_FIFO_CNT_RK3588 GENMASK(7, 5)
 #define RKCANFD_REG_RX_FIFO_CTRL_RX_FIFO_FULL_WATERMARK GENMASK(3, 1)
 #define RKCANFD_REG_RX_FIFO_CTRL_RX_FIFO_ENABLE BIT(0)
 
@@ -331,6 +332,11 @@
  * rarely with the standard clock of 300 MHz, but almost immediately
  * at 80 MHz.
  *
+ * Tests on the rk3588 show the same empty FIFO condition.
+ * In that setup rx_fifo_empty_errors increments when the bus
+ * transitions from idle to high CAN-FD load and stops growing once
+ * the bus reaches a steady state.
+ *
  * To workaround this problem, check for empty FIFO with
  * rkcanfd_fifo_header_empty() in rkcanfd_handle_rx_int_one() and exit
  * early.
@@ -344,6 +350,8 @@
 /* Erratum 6: The CAN controller's transmission of extended frames may
  * intermittently change into standard frames
  *
+ * Tests on the rk3588 show the same problem.
+ *
  * Work around this issue by activating self reception (RXSTX). If we
  * have pending TX CAN frames, check all RX'ed CAN frames in
  * rkcanfd_rxstx_filter().
@@ -408,6 +416,18 @@
  *     cansend can0 002##07217010000000000
  *   DUT:
  *     candump any,0:0,#FFFFFFFF -cexdHtA
+ *
+ * Tests on the rk3588 show a different CAN-FD failure mode: these two
+ * CAN-FD frames do not trigger Error Interrupt or Error-Warning. CAN-FD
+ * frames without bitrate switching work in this setup, but BRS with a
+ * data bitrate different from the nominal bitrate drives the controller
+ * bus-off immediately.
+ *
+ * To reproduce:
+ * host:
+ *   cangen can0 -I 2 -Li -Di -p 10 -f -g 1 -c32 -b
+ * DUT:
+ *   cansequence -rv can1 -f
  */
 #define RKCANFD_QUIRK_CANFD_BROKEN BIT(12)
 
@@ -424,6 +444,9 @@
  *     cansequence -rv -i 1
  *
  * - TX starvation after repeated Bus-Off
+ *   Tests on the rk3588 show the same problem. In a
+ *   10-cycle Bus-Off recovery test, 9 cycles failed to send after the
+ *   controller restarted.
  *   To reproduce:
  *   host:
  *     sleep 3 && cangen can0 -I2 -Li -Di -p10 -g 0.0
@@ -434,6 +457,7 @@
 enum rkcanfd_model {
 	RKCANFD_MODEL_RK3568V2 = 0x35682,
 	RKCANFD_MODEL_RK3568V3 = 0x35683,
+	RKCANFD_MODEL_RK3588 = 0x3588,
 };
 
 struct rkcanfd_devtype_data {
-- 
2.34.1